Plasma arc torches are widely used for cutting metallic materials and can be employed in automated systems for automatically processing a workpiece. The system can include the plasma arc torch, an associated power supply, a positioning apparatus, and an associated controller. At least one of the plasma arc torch and the workpiece can be mounted on the positioning apparatus which provides relative motion between the torch and the workpiece to direct the plasma arc along a processing path.
A plasma torch generally includes an electrode and a nozzle having a central exit orifice mounted within a torch body, electrical connections, passages for cooling, passages for arc control fluids (e.g., plasma gas), and a power supply. A swirl ring can be employed to control fluid flow patterns in the plasma chamber formed between the electrode and nozzle. The torch produces a plasma arc, a constricted ionized jet of a gas with high temperature and high momentum. Gases used in the torch can be non-reactive (e.g., argon or nitrogen) or reactive (e.g., oxygen or air). In operation, a pilot arc is first generated between the electrode (cathode) and the nozzle (anode). Generation of the pilot arc can be, for example, by a high frequency, high voltage signal.
The consumables (e.g., electrode, nozzle, etc.) in a mechanized torch are replaced frequently, for example, the consumables can be replaced every shift or approximately every eight hours the torch is in use. To replace the consumables, the torch is disconnected from the power supply to ensure the safety of the operator. The connector assembly that connects the torch to the power supply can be located within or blocked by portions of a gantry of the positioning device. Often, the operator cannot see the connector assembly and must align several gas and coolant tubes, power and signal connections without being able to have an adequate view of the connection point. (See e.g., FIG. 3B of U.S. Pat. No. 5,624,586 as an example of the connections to be made.) This can result in the gas and/or coolant tubes being misaligned, which can lead to damage of the plasma arc torch and/or receptacle.